Q-ball imaging in constant solid angle and a Hough transform approach to diffusion MRI tractography
Speaker: Iman Aganj , University of Minnesota
Date: October 14 2010
Time: 2:30PM to 3:30PM
Location: 32-D507
Host: Polina Golland, CSAIL
Contact: Polina Golland, x38005, polina@csail.mit.edu
Relevant URL: NOTE SPECIAL TIME
Q-ball imaging (QBI) is a high angular resolution diffusion imaging (HARDI)
technique which has been proven very successful in resolving multiple
intravoxel fiber orientations in MR images. The standard computation of the
orientation distribution function (ODF, the probability of diffusion in a
given direction) from q-ball data uses linear radial projection, neglecting
the change in the volume element along each direction. This results in
different spherical distributions that are not as sharp as expected, and
generally require post-processing. In this talk, I will first present a new
technique that, by considering the solid angle factor, uses the
mathematically correct definition of the ODF and results in a dimensionless
and normalized ODF expression computed from single or multiple q-shells.
Then I will continue by introducing a global probabilistic fiber tracking
approach based on the voting process provided by the Hough transform. The
proposed framework tests candidate 3D curves in the volume, assigning to
each one a score computed from the diffusion images, and then selects the
curves with the highest scores as the potential anatomical connections. I
will show experimental results on simulated and real HARDI volumes.
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